I don't see any reason why you couldn't do them in any color that's available. Some of the aftermarket parts are available in many different colors. Whistle Pig barrels come readily to mind.
The only downside to color anodizing is that it can't be Type III hard anodizing. Thus, it will scratch and show wear much faster that the original factory finish.
You could also Cerakote the parts. It's a 2 part baked on finish that is very wear/scratch resistant. In fact there are some gun companies that now offer their guns Cerakoted directly from the factory. IIRC Colt is one.